NO. 2212. A NEW SPECIES OF EXTINCT HORSE— HAY. 443 



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It will be seen that the Yukon horse is quite distinct from the 

 one described by Tseherski. It is smaller, and had a head somewhat 

 broader relatively to the length, and a considerably longer face. 

 The teeth of the Siberian horse are relatively broad and the proto- 

 cone approaches in width that of E. lamhei; but in many important 

 features the teeth are quite different. 



A careful examination of Tscherski's figure 4 of his plate 5 

 shows that the part of the maxilla behind the infraorbital foramen 

 in the Siberian horse was not swollen as it is in the Yukon species; 

 but was, rather, considerably excavated. 



EXPLANATION OF PLATES. 



Plate 56. 

 Equus lamhei. Type. 

 Fig. 1. View of left side of skull. X .318. 



2. View of lower premolars and molars. X 1. 



Plate 57. 

 Equus lamhei. Type. 

 Fig. 1. View of lower surface of skull. X .33. 



2. View of grinding faces of premolars. X 1. 



3. View of grinding faces of molars. X 1. 



Plate 58. 

 Equus lamhei. Type. 

 Fig. 1. View of upper surface of skull. X i. 



2. View of grinding faces of lower premolars and moljirs. X 1. 



